Creep Relaxation of Residual Stresses Around Cold Expanded Holes

2000 ◽  
Vol 123 (1) ◽  
pp. 125-131 ◽  
Author(s):  
A. A. Garcia-Granada ◽  
V. D. Lacarac ◽  
P. Holdway ◽  
D. J. Smith ◽  
M. J. Pavier
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Mechanical Load ◽  
Three Dimensional ◽  
Standard Technique ◽  
New Method ◽  
Near Surface ◽  
Cold Expansion ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The cold expansion of fastener holes in aircraft components is a standard technique to improve fatigue life. There is concern that the beneficial residual stresses arising from cold expansion may relax due to creep. This paper describes experimental measurement and finite element prediction of cold expansion residual stresses and their redistribution after creep, with and without additional mechanical load. Experimental measurements of near-surface stresses used an X-ray diffraction technique while average through-the-thickness stresses were measured using a new method based on Sachs’ boring. This new method allowed non-axisymmetric residual stresses to be measured, as was the case when creep relaxation occurred with mechanical load. Axisymmetric and three dimensional finite element analyses were used to predict the stress distribution through the thickness of the component showing good agreement with measurement. Creep relaxation of residual stress does indeed occur, but some benefit of the cold expansion remains, particularly when creep relaxation is combined with the application of mechanical load.

scholarly journals Three-dimensional finite element simulation of residual stresses in UIC60 rails during the quenching process

2017 ◽  
Vol 21 (3) ◽  
pp. 1301-1307 ◽  
Author(s):  
Nejad Masoudi ◽  
Mahmoud Shariati ◽  
Khalil Farhangdoost
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Analysis Model ◽  
Element Analysis ◽  
Quenching Process ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The aim of this paper is to develop means to predict accurately the residual stresses due to quenching process of an UIC60 rail. A 3-D non-linear stress analysis model has been applied to estimate stress fields of an UIC60 rail in the quenching process. A cooling mechanism with water spray is simulated applying the elastic-plastic finite element analysis for the rail. The 3-D finite element analysis results of the studies presented in this paper are needed to describe the initial conditions for analyses of how the service conditions may act to change the as-manufactured stress field.

Three Dimensional Finite Element Analyses of Welding Residual Stresses of a Repaired Weld

2018 ◽  
Author(s):  
Mingya Chen ◽  
Weiwei Yu ◽  
Fei Xue ◽  
Francis Ku ◽  
Zhilin Chen ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Nuclear Power ◽  
Power Plants ◽  
Three Dimensional ◽  
Fe Model ◽  
Dimensional Finite Element ◽  
Surge Line ◽  
Line Slope ◽  
Three Dimensional Finite Element

The objective of this study is to correct installation non-conformance of a surge line using the excavation and re-weld method which is widely used in nuclear power plants. The surge line with a backslope was not at the required design level after initial installation. In order to solve the problem, a repairing technology is shown as follows: the weld was successively excavated and welded again while the surge line slope was corrected with the help of jacks. Because many of the degradation mechanisms relevant to power plant components can be accelerated by the presence of welding residual stresses (WRS), the WRS caused by the repairing process need to be studied. In this paper, the WRS simulation technique employed in this project is sophisticated. It utilizes a 3-D finite element (FE) model, and simulates the weld sequencing and excavation. Moreover, the WRS simulation performed in this project not only uses the un-axisymmetric model, but also considers the deformation caused by the external jacking loads. The results show that the repairing process is effective, and strain damage induced by the welding repair is also acceptable.

Three Dimensional Finite Element Analysis of a Split-Sleeve Cold Expansion Process

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
S. Ismonov ◽  
S. R. Daniewicz ◽  
J. C. Newman ◽  
M. R. Hill ◽  
M. R. Urban
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Expansion Process ◽  
Element Analysis ◽  
Cold Expansion ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A cold expansion process is used to prolong the fatigue life of a structure under cyclic loadings. The process produces a beneficial compressive residual stress zone in the hole vicinity, which retards the initiation and propagation of the crack at the hole edge. In this study, a three-dimensional finite element model of the split-sleeve cold expansion process was developed to predict the resulting residual stress field. A thin rectangular aluminum sheet with a centrally located hole was considered. A rigid mandrel and an elastic steel split sleeve were explicitly modeled with the appropriate contact elements at the interfaces between the mandrel, the sleeve, and the hole. Geometrical and material nonlinearities were included. The simulation results were compared with experimental measurements of the residual stress. The influence of friction and the prescribed boundary conditions for the sheet were studied. Differences between the split-sleeve- and the non-split-sleeve model solutions are discussed.

Study of Parameter Effects on Residual Stresses and Thermal Deformation of Brazed Plate-Fin Structure Using Finite Element Method

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Hu Chen ◽  
Jian-Ming Gong ◽  
Shan-Tung Tu ◽  
Lu-Yang Geng
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Thermal Deformation ◽  
Three Dimensional ◽  
Negative Effects ◽  
Element Analysis ◽  
Vacuum Brazing ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Clamping Pressure

The brazed plate-fin structure is the key component of a compact plate-fin heat exchanger. The residual stresses and thermal deformation induced by vacuum brazing may bring negative effects on the quality and the life of the plate-fin structure. Thus, it is important to optimize the brazing parameters in order to minimize such effects. This paper presents a three-dimensional finite element analysis for determining the residual stresses and thermal deformation of a three layered stainless steel plate-fin structure fabricated by nickel-based brazing. The features of residual stresses and thermal deformation distribution are discussed. The effects of three major brazing parameters including brazing temperature, clamping pressure load, and filler metal on the residual stresses and thermal deformation are investigated, respectively.

Finite Element Study of Factor Effects on Residual Stresses and Thermal Deformation of Brazed Plate-Fin Structure

2007 ◽  
Vol 353-358 ◽  
pp. 473-476
Author(s):  
Hu Chen ◽  
Jian Ming Gong ◽  
Shan Tung Tu ◽  
Lu Yang Geng
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Thermal Deformation ◽  
Three Dimensional ◽  
Negative Effects ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Major Factors ◽  
Three Dimensional Finite Element ◽  
Clamping Pressure

The brazed plate-fin structure is the key component of a compact plate-fin heat exchanger (PFHE). The thermal deformation and residual stresses induced by vacuum brazing may bring negative effects on the quality and the life of the plate-fin structure. Thus it is important to optimize the brazing parameters in order to minimize such effects. This paper presents a three-dimensional finite element analysis for determining the thermal deformation and residual stresses of a three layers of stainless steel plate-fin structure fabricated by nickel-based brazing. The feature of thermal deformation and residual stresses distribution are discussed. The effects of three major factors including brazing temperature, clamping pressure and filler metal on the thermal deformation and residual stresses are investigated respectively.

Evaluation of residual stress assessment methods using a repair weld benchmark

2010 ◽  
Vol 45 (3) ◽  
pp. 197-208
Author(s):  
L K Keppas ◽  
R C Wimpory ◽  
D E Katsareas ◽  
N K Anifantis ◽  
A G Youtsos
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Assessment Tools ◽  
Temperature History ◽  
Stress Assessment ◽  
Dimensional Finite Element ◽  
Full Annealing ◽  
Three Dimensional Finite Element

A simple design of a letterbox-type repair weld on a plate is evaluated as a benchmark problem. Residual stresses are recorded using the non-destructive neutron diffraction technique and compared with predictions by full three-dimensional finite element modelling. The comparison is performed over a number of path lines in an attempt to evaluate both methods as potential residual stress assessment tools, for weld repairs. The proposed finite element methodology is based on uncoupled quasi-static thermoelasticity and incorporates the element activation–deactivation technique for simulating weld deposition. Sensitivity analysis indicates that the effect of heat loss due to radiation on predicted residual stresses is negligible, whereas incorporation of full annealing into the model is recommended. The diffractometer used, is STRESS-SPEC, located at the FRMII research reactor (Munich, Germany) and comprises a highly flexible monochromator arrangement and a two-dimensional position-sensitive 3He detector. The success of the repair weld benchmark design is illustrated by not only the satisfactory correlation between experimental and computational results in the form of residual stress but also temperature history data.

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